Owlet smart sock

So I purchased my owlet smart sock from babies r us online in February. I lost the receipt and now am having a battery issue that owlet confirmed via tech support. Unfortunately now that babies r us is out of business I can’t get a copy of the receipt and owlet is telling me that I’m pretty much shot out of luck. I told them I can send them a copy of my daughters birth certificate to prove that she is less then I year old (she’s only 7 months old) but they will do nothing to help me! I’m so upset because I spend $300 bucks on it less then 7 months ago and now they are telling me I have to buy the replacement price which is $140 bucks. Idk what to do. Anyone have the same issue with them and got it resolved. Any help would be greatly appreciated since I really don’t want to have to but the replacement part. Thanks in advance for your input